Automatically disable Shared Folder if server files_sharing app is disabled

**Is your feature request related to a problem? Please describe.**
Hello ! If a Nextcloud instance has the `files_sharing` app disabled, the user experience should reflect that.

**Describe the solution you'd like**
The user interface won't show anything related to file sharing within the Nextcloud instance, but still allows sending a file that the Nextcloud App is first downloading then forwarding to another app through local storage on the device.

**Describe alternatives you've considered**
Explaining to users of said instance why the Shared Folder loads indefinitely.